The present disclosure generally relates to power supply devices for supplying an electrical power to a load such as an electrical power supply grid. In particular, the present disclosure relates to an apparatus adapted for combining electrical outputs of electrical generators of different wind turbines. Furthermore, the present disclosure relates to a method for combining electrical outputs of electrical generators of different wind turbines.
Wind turbines are of increasing importance as environmentally safe and reliable energy sources. Typically, wind turbines are arranged within wind turbine farms, briefly referred to as “wind farms”. These wind farms are typically located in geographical regions where appropriate environmental conditions for running a large number of wind turbines prevail.
In an individual wind turbine, the kinetic energy of an air stream is converted into electrical energy. To this end, an air stream energy or wind energy is converted into rotational energy which can be used to drive an electrical generator. Typically, each wind turbine includes these electrical generators which provide an electrical output on the basis of the rotational energy input. In wind farms, the outputs of individual electrical generators are combined to provide an electrical energy output e.g. to an electrical power supply grid.
For generation and/or conversion of an electrical output energy of an electrical generator of a wind turbine in a predetermined frequency and/or voltage range, harmonics with respect to a fundamental frequency or a grid frequency (e.g. 60 Hz in the US and 50 Hz in Europe) may occur. These harmonics may be superposed onto the electrical output currents of the individual electrical generators and may cause problems e.g. with respect to electrical and electronic components arranged within a wind farm. Typically, there is an admissible level of harmonics which is allowed within a wind farm and/or at an energy output unit connecting the wind farm to an electrical power supply grid.